According to a press release from the organization:

“It is with regret that we tell our members and all of those who treasure free speech and the separation of religion and government that American Atheists and Adams Outdoor Advertising have mutually agreed to remove the billboards immediately,” said Amanda Knief, American Atheists’ Managing Director.

“No subject, no idea should be above scrutiny—and this includes religion in all forms,” Ms. Knief said. “We are saddened that by choosing to express our rights as atheists through questioning the religious beliefs of the men who want to be our president that our fellow citizens have responded with vitriol, threats, and hate speech against our staff, volunteers, and Adams Outdoor Advertising.”